Radiotelegraphy



Patented May 4, 1920.

wmvfofl I... FULLER A TTOR/VEYS UNITED STATES PATENTOFFIGE.

LEONARD F. FULLER, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO FEDERAL TELEGRAPH COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

RADIOTELEGRAPHY.

Patented May 4, 1920.

Application filed September 4, 1917. Serial No. 189,523.

To all whom it may concern: 7

Be it known that I, LEONARD F. FULLER, a citizen of the United States, anda resident of the city and county of San Francisco and State of California, have invented certain new and useful Improvements in Radioteleg raphy, of which the following is a specification.

The invention relates to means of signaling and particularly to means of signaling with arc radio transmitters.

An object of the invention is to provide means for signaling involving interrupting and reestablishing the arc.

Another object of the invention is to provide means for interrupting and reestablishing the are by varying the length of the arc b The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where I shall outline in full that form of the invention which I have selected for illustration in the drawing accompanying and forming part of the present specification. It is to be understood,

however, that the invention as expressed in the claims is not limited to the specific embodiments shown in the drawing.

The drawing is a diagrammatic repre: sentation of the signaling system of my in vention.

The transmission system comprises an arc oscillation generator, including the electrodes 2-3 between which the arc is formed.

- One of the electrodes, preferably the negative electrode ,3, is grounded and the other electrode 2 is connected to the antenna 4.- through the' variable inductance coil 5. Direct current is supplied to the arc radio generator by the generator 6 and a choke coil 7 is arranged in the lead 8 which is connected to the electrode 2. The are is subjected to a strong transverse magnetic field produced by the magnet coils 9 which may be separately excited or arranged in series in the lead 8.

I Signaling is accomplished by igniting the arc and subsequently extinguishing it by increasing the distance between the electrodes, and the distance is preferably increased by moving one of the electrodes. In operatlon,

distance that the arc goes out and suhscquently the length of the gap is decreased to its proper oscillating arc length and the arc is reestablished by 'a spark or other means. These operations are performed automatically and at telegraphic speed, and signallng is accomplished with a transmission key in the usual manner.

Secured to the electrode v2 and insulated therefrom is a. solenoid core 12 which is movable in a directionto increase the length of the arc gap by a spring 13 and is movable in the opposite direction by the efi'ect'of the current flowing in the solenoid 14. The solenoid is arranged in series with a battery 15 and the-signaling key 16, which, when depressed, closes the circuit and causes the electrode 2 to be moved to shorten the arc gap to its proper oscillating arc length. An

ear projection 17 on the core 12 contacts with a stop 18, as the core moves. forward, and stops the electrode 2 so that the proper oscillating arc gap is produced. A stop 19 halts the movement of the electrode on'its backward movement. As the electrodes wear, the length of the arc is adjusted to preserve the proper oscillating length by a nut 21 engaging the screw 22 secured to the normally stationary electrode 3. The nut 21 is disposed between stops 23, so that the electrode is moved longitudinally by rotation of the nut.

I have shown one means for reigniting the are after the length of the arc gap has been decreased to the proper oscillating arc length. Connected across the arc is a spark circuit containing the spark gap 24, the secondary of the transformer 25 and the ca-- pacity 26, shunting the secondary. A stop a ping resistance 27 is arranged between the spark gap and the antenna side of the arc to prevent direct current sufiicient to maintain an arc across the gap 24 from following the radiofrequency current across the spark %illp 1e and passing through the secondary.

primary of the transformer is in series with an alternating current generator 28 and a switch 29 connected to and insulated from the. key 16. When the key is closed, the

' electrodes are brought together and simultaneously, the circuit through the primary of the transformer is closed, producing a high potential in the spark circuit and producing a spark across the spark gapwhich sets up radio frequency surges which-ignite the arc. When the key is released, the sprin 13 increases the length of the are gap an causes the arc to be extinguished.

I claim:

1. An are system for radio signaling, comprising two electrodes, means for maintaining an are" between said electrodes, means for increasing the distance between the electrodes to such length that the arc is extinguished and means for reiistablishing the are.

2. An are system for radio slgnalmg,

comprising two spaced electrodes, means for producing a voltage of sufficient magnitude to maintain an are between the spaced electrodes, means for increasing the distance between the electrodes to such length that the arc is extinguished, means for decreasing the distance between the electrodes and means for producing a voltage of greater magnitude between the electrodes for re'c'stablishing the arc.

An are system for radio signaling, comprising twoelectrodes, means for main taining an are between said electrodes,

means for increasing the distance between the electrodes to such length that the are is extinguished, means for decreasing the length of the are gap to the proper oscillating arc length, and means for igniting the are between the electrodes so spaced.

4. An are system for radio signaling, comprising two electrodes spaced apart a greater distance than the ,proper oscillating arc length, means for decreasing the distance between the electrodes to proper oscillating arc length and means for establishing an are between said electrodes so spaced.

5. An are system for radio signaling,

comprising two electrodes spaced apart a 7. An are system for radio signaling, comprlsing two electrodes spaced apart a greater distance than the proper oscillating 8. An arcsystem for radio signaling,

comprising two electrodes spaced apart a greater distance than the proper oscillating arc length, a spring tending to hold said electrodes apart, a solenoid, a core attached to one of said electrodes and associated with said solenoid, the energizing of the solenoid c1rcu1t operating to move said electrode toward the other.

9. An are system for 'adio signaling, comprising two electrodes spaced .apart a greater distance than the proper oscillating arc length, a spring tending to hold said electrodes apart, a solenoid, a core attached to one of said electrodes and associated with said solenoid, theenergizing of the solenoid circuit operating to move said electrode toward the other, and means for stopping the movement of the electrode when the distance between the electrodes is equal to the proper oscillating arc length.

10. An are system for radio signaling comprising two electrodes, means for maintaining an are between said electrodes, means for increasing the distance between the electrodes to such length that the arc is extinguished, means for decreasing the distance between the electrodes, and means for producing a. spark between the electrodes so spaced whereby the arc is reestablished.

11. An are system for radio signaling comprising two electrodes between which an arc is formed, an antenna circuit connected to said electrodes, means for increasing the distancebetween'the electrodes whereby the arc is extinguished, means for decreasing the distance between the electrodes and means for producing radio frequency surges in the antenna circuit which reignite the arc. In testimony whereof, I have hereunto set my hand at San Francisco, California, this Jth day of August 1917.

LEONARD F. FULLER.

In presence of- 

